If you're lazy, one of the better kits I've tried is Gourmantra... I bought this for the first time at CNE a few years ago, but have seen it at Metro and Costco (might not be at Costco any more). Comes with spices, tomato paste, and rice. You need chick peas and an onion.Their butter chicken is also good. Add chicken and cream I think.

Why do you need to find a chana masala spice mix? You can use garam masala, which you'll find in any Indian store (or even better, buy the individual spices in small quantities at Bulk Barn or an Indian shop and toast and grind your own blend). The only oddball ingredient outside of the garam masala is dried mango powder (amchoor), which you can also buy in any Indian shop. If you can't find it, lemon juice will be a reasonable substitute. I had a Punjabi roommate in university who made chana masala regularly and used her mom's homemade garam masala and no other dried spices.

Yes, that's a lot cheaper too, which is why I started with "If you're lazy". I made butter chicken sauce from scratch before and bought all the individual spices which I remember were fairly cheap. But then my whole pantry started smelling like the spices and I had to store them in air tight containers. As someone who only makes this stuff a few times a year, I'd gladly pay the premium for a pre-measured kit where the spices are sealed in a foil bag.

I maybe lazy but I think a more accurate description of the situation is that I had never seen or heard of Chana masala in my life before late last week.. So using a mix is a rationale thing to do at first.